Light emitting devices, such as light emitting diodes or laser diodes, using group III-V or II-VI compound semiconductor materials may produce light of various colors, such as red, green, blue, and ultraviolet light, due to development of thin film growth techniques and device materials. Further, the light emitting devices may produce white light having high efficiency using phosphor materials or through color mixing. The light emitting devices have advantages, such as low power consumption, semi-permanent lifespan, rapid response time, stability, and environmental friendliness as compared to conventional light sources, such as fluorescent lamps and incandescent lamps.
Therefore, these light emitting devices are increasingly applied to transmission modules of optical communication units, light emitting diode backlight units substituting for cold cathode fluorescent lamps (CCFLs) constituting backlight units of liquid crystal display (LCD) devices, lighting apparatuses using white light emitting diodes substituting for fluorescent lamps or incandescent lamps, head-lights for vehicles and traffic lights.